1. Field of the Invention
The present invention relates to a terminal connection device for a power cable, in particular a medium or high voltage power cable, and to a method of connecting an end of a medium or high voltage power cable to a connection point.
2. Description of the Prior Art
It is generally known to use radially shrinkable sleeves for enclosing an electrical cable connected to another electrical cable or a stop end. An example of a known radially shrinkable sleeve for covering cable terminations either of cable connectors or stop ends is described in EP-B-0 435 569. The shrinkable sleeve comprises a dielectric material as an intermediate insulating layer, an electric field control inner layer combined with a partially coated inner conductive layer, and an electrically conducting outer layer. Such a multi-layer sleeve is preferably made by extrusion and preferably comprises silicone or EPDM.
When making cable splices or cable end terminations by means of a known radially shrinkable sleeve it is necessary that on one side of the connector a free space is provided (parking position), which corresponds to the complete length of the shrinkable sleeve. After the cable connection is established, the shrinkable sleeve is centered over the cable connection and is then shrunk down either by the application of heat or by the removal of an external or internal support maintaining the shrinkable sleeve in a radially extended state. EP-B-0 541 000 discloses a radially shrinkable sleeve which in its radially expanded state is held by two removable support cores located adjacent each other. Another radially shrinkable sleeve having individual support cores for different sections of the sleeve is disclosed in EP-B-0 966 780. In this known assembly, different sections of the sleeve are concentrically arranged by folding back the sleeve, wherein the individual sections are maintained in their respective radially expanded states by means of removable support cores or similar support elements.
WO90/13933 discloses a plug-in connection, in particular a sleeve for high-voltage plastic cables, comprising an electrical insulator fitting closely onto cable ends, the cable insulator having an electrically conducting stress-controlling body for screening cable conductor connecting elements received herein, an insulating body surrounding the stress-controlling body and an electrically conducting sheath surrounding the insulating body completely or partially. The insulator is provided with axial close-fitting passages merging into the space in the stress-controlling body for the cable conductor connecting elements. The cable conductor connecting elements comprise at least one plug part and at least one counter-plug part and means for mutually locking the plug part and the counter-plug part
WO96/10851 aims to provide a simplified connection system for high voltage power cables having ratings up to 400 KV and above, in particular a common cable connection system for all accessories and interconnection. The connection system uses a generally applicable interface for interconnection with a number of different apparatus and includes a cable termination consisting of an elastomeric body, integrated therein is a stress relief device, a connector shield, an insulation having a conical interface surface and an outer conductive screen and a rigid insulator having a conical interface surface corresponding to the interface surface of the cable termination.
When an existing cable termination has to be replaced with a new one (due to repair/maintenance or feature upgrading) without the need to replace the existing power cables (i.e., retro-fitting), the most difficult operation is to re-connect the existing cables to the new termination. Replacing a cable termination requires cutting off the existing cable termination in its installed location. Typically this is a switchgear enclosure, a bus bar cabinet, or adjacent generators, motors, transformers, etc. When the existing cable termination is removed, the remaining power cable is not long enough to be terminated with a standard cable termination and re-connected again to the switchgear pole, bus bar, generator, etc.
Additionally, when a repair is required, the time it takes to reconnect the power cable is a concern in terms of impact on service continuity and penalty costs for energy network management.
Accordingly, there is a need for an improved cable termination, in particular for medium or high voltage power cables, that provides a structural/dimensional solution suitable to be quickly installed and working inside a very limited space.